Transformer Oil Purifiers
Transformers around the world are filled with a liquid commonly known as transformer oil. This oil is a petroleum-based hydrocarbon that has been selected because of its high dielectric strength and overall chemical stability.
Transformer oil deterioration and degradation refer to the adverse physical and chemical processes within the insulating liquid that negatively impact its performance and longevity. In order to provide the greatest level of efficiency, transformer oil deterioration must be minimized.
Transformers used in power distribution and transmission carry a lot of significance and must function reliably and efficiently for a longer amount of time to recoup the high upfront costs.
In most cases, the quality of the transformer oil plays a key role in ensuring that the transformer itself lives a long and efficient life. Unfortunately, the quality decreases as the oil is used.
Deterioration of liquids in transformers can be caused by contamination, overheating, electrical stress and oxidation. However, there are two additional processes occurring in the transformer oil that further deteriorate the liquid.
The first is moisture contamination. This moisture, or water, in this case, is present in the transformer in the form of tiny droplets (known as emulsified water) or sometimes just a collection of free water at the bottom of the device (known as demulsified water).
Demulsified water contamination is easily taken care of by extracting the water through filtering or centrifugal treatment. Emulsified water, on the other hand, requires vacuum dehydration to be removed.
Both forms have profound effects on the insulating properties of the transformer oil because they reduce the overall dielectric strength of the liquid. Some of the dissolved water also gets absorbed over time by the paper insulation of the transformer which further affects its insulation properties. To make matters worse, the water content in the paper is especially difficult to remove and requires drying with heat and vacuum.
The second, less common deterioration, occurs because of oxidation. This type is much slower than the effects of moisture, but its effects are often much more serious. Oxidation not only creates acids in the transformer oil but increases the formation of sludge.
A key factor in oxidation speed is temperature. Transformers operating in higher temperatures, for example, are especially susceptible to this kind of oxidation.
To keep oxidation at a minimum, oxygen must be excluded from the transformer as much as possible. This is because oxygen interacts with the transformers inner atmospheric oxygen and oxygen occurring in moisture.
Therefore, gaskets and seals must be maintained regularly and water content needs to be kept as low as possible through the process of vacuum dehydration using oil purifying plants.
The lifetime of a transformer and its paper insulation can be increased significantly by preventing deterioration of transformer oil.
Transformer Oil Purifiers may sometimes be called High Vacuum Oil Purifiers because oil is generally dehydrated to less than 20 PPM in order to meet transformer processed oil specifications. In order to receive the name high vacuum, it requires a two-stage vacuum pump system.
The first stage vacuum pump, sometimes known as a rouging pump, will get you down to about 20 torrs, and a second booster pump will enable you to lower the total vacuum to as low as .5 torr. When oil is exposed to this high of a vacuum under .5 torr, the total dissolved water content will drop to as low as 2 to 5 PPM.
Transformer Oil Purifiers have another function: to dry out transformer windings.
Standard transformer windings are insulated with cellulose compounds that have an affinity for water.
Whenever work is performed on a transformer, oil from within must be drained for maintenance purposes. As this occurs, outside air will enter and contaminate the windings with water molecules. Unfortunately, this process is unavoidable when maintenance is carried out on a transformer.
To try and reduce this problem, however, maintenance crews will transfer the oil into a separate reservoir.
The Transformer Oil Purifier is then connected to a sealed transformer without oil and a high vacuum is connected. The vacuum will pull water from the transformer windings and out of the transformer altogether. Moisture and other dissolved gasses are then put back into the atmosphere through the Vacuum Oil Purifiers Vacuum Pump System.
As this occurs, the Vacuum Oil Purifier circulates oil within the external tank. After 10 to 20 passes, the oil is typically ready and is tested and verified to be under 20 PPM before filling the transformer back up.
Once the transformer is filled with the dehydrated and degassed particulate free oil, it is sealed with a positive blanket of dry nitrogen. This dry nitrogen helps to ensure that outside air and contaminants remain outside of the transformer during this process.
Transformer Oil or Dielectric Oil Purifiers can also be used as an in-line filtration process to transfer fluids between reservoirs. They may also be connected to a reservoir or transformer where they are installed into a circulation loop, but this is typically performed when the transformer is inactive and not online. This process may also be known as Kidney Loop Filtration and is very similar to our own kidney's process of circulating blood throughout the body. After 10 to 20 passes, particulate contamination will generally meet or exceed new oil cleanliness results.
Customers can rent or purchase a custom Transformer Oil Purifier through Hydrocarbon Filtration Systems and will often receive a system that meets their needs within a few hours. We have equipment in warehouses all across the United States, most of which have Transformer Oil Purifiers in stock.
Many of our filtration systems are NEMA 4 Electrical Compliant and can be operated outdoors in most weather conditions. We also specialize in NEMA 7 explosion proof systems that meet Class 1, Division 2, and Groups C&D electrical specifications.
For ease of logistics and mobility, most of our systems are skid mounted with protective cages and equipped with lifting lugs and forklift slots on all four sides. Our systems can easily be moved by standard forklifts, overhead cranes, flatbed trucks, cargo containers, and trailers.
Most systems are 460 V/3 Phase Power, and require anything between 20 to 100 amps of power supply, depending on the size and load of the system. They range in size from 3 feet deep by 3 feet wide by 4 feet tall and 6 feet deep by 16 feet wide by 7 feet tall, and between 400 and 9,500 pounds respectively.